Galaxy S6 battery mod: S7 Edge battery

I am pretty happy with my Galaxy S6 – its an excellent phone. Amazing CPU and GPU performance, fast storage (though I only got the 32 GB version), good software support (Samsung updated it to Nougat) and of course the beautiful AMOLED 1440p display – it certainly is one of the best phones released by Samsung. One issue I had with it, however was its battery life. At the beginning, while not amazing, the battery performance was okay – I was getting about 30 h with medium-heavy usage, which fast charging alleviated a lot. However, with using fast charging all the time, after an year and a half, my average battery life has dropped to about 18 hours, which while manageable is far from perfect.

So replacing the battery on the S6 is no easy task – as is with most phones manufactured recently – the days, where you could pop the back open and change it are gone and you have to do some pretty complicated stuff to get to that battery.

What you need?

In order to replace the battery on the Galaxy S6, you will need the following stuff:

hot air gun (hairdryer probably will work as well)

a suction cup

screwdriver set (for 3.5 mm Philips #00 screws)

hot silicon gun

S7 Edge battery (obviously)

a toothpick or another thin hard object

a thin hard plastic tool

Why S7 Edge battery?

Battery capacity comparison:

S6 – 2550 mAh

S6 Edge – 2600 mAh

S7 – 3000 mAh

S7 Edge – 3600 mAh

So it seems that the S7 battery is identical in dimensions with the S6 one and the S7 Edge battery is only slightly thicker and has much more capacity. This means that the S7 is easy replacement and with some luck we will be able to squeeze the larger S7 Edge battery in the S6 body… yeah – nothing dangerous about that. Not like Samsung got in any trouble attempting to push a large battery into a thin phone body…

Do this with care and on your own responsibility.

So armed with a lot of bravery and optimism let’s proceed to the actual work.

Opening the phone

I used this excellent video from WitRigs that covers the S6 battery replacement process very quick and thorough, so you can check it out, before proceeding to get a visual idea of what follows.

Before you begin, remove the sim card tray (here you use the toothpick/needle).

We will need to heat the back of the phone, in order to loosen the adhesive that holds it in place. While the electronics are pretty safe – after all they are made to be soldered, some of the other components like the screen and the battery may be damaged, in case of excessive heat. Note however that the adhesive that holds the back is really, really strong and you will need to both heat it up a lot and pull it very hard to separate it from the midframe.

So, first begin by heating the phone with the hot air gun. Make sure that you get it really hot, so the adhesive can loosen, but proceed carefully and slowly so you don’t burn something (like your hands).

Put the suction cup to the back of the phone and pull gently but firmly. Apply more force and/or heat, until you notice a thin split between the back cover and the midframe.

Insert your plastic tool there and slide it across the edges of the cover to break the adhesive from it. If it becomes too hard – don’t push it too much and reheat as needed. Take care, because the glass material, the back is made of, is bendy, but still cracks much easier than plastic.

After you break the adhesive tape from all sides, separate the cover and put it aside.

Removing the old battery

The black thing covering the battery is the NFC antenna / wireless charging. Peel its sides off the midframe to allow easier access to the battery.

There are 13 x 3.5 mm Philips #00 screws that hold the midframe to the mainboard and display assembly. Unscrew those and make sure to not lose them.

While holding the midframe from the sides with one hand, push on the battery with the other. Apply force until the mainboard and display assembly “pops” out of the midframe.

Now remove the cable that connects the battery to the mainboard and proceed to take it off.

The battery is held to the front of the phone with a similar adhesive, so you will need to insert something hard and plastic to pop it out. Reheat if necessary.

Note: Puncturing the battery can cause the lithium inside to ignite or even explode! Do not use metal tools to separate it and be very careful!

Now we see here that the both batteries have very similar dimensions, the S7 Edge one is even a bit narrower.

However, it seems just a tiny bit thicker than the S6 one. (S6 on the left, S7 Edge on right)

Putting the new one in

Lets put it in the place of the original one and connect it to the mainboard. Take note that the connection cable is a bit longer, so you will need to bend it.

The new battery should sit well in the phone.

Let’s proceed to put the mainboard display assembly back in the midframe. Make sure that you begin screwing from opposite sides and not sequentially in order to avoid stressing the screw threads and assure that everything gets back in place.

I think that the thickness difference between the original S6 battery and the S7 Edge one is about 1 mm, so it is definitely a feasible mod.

Closing and sealing the phone

Now heat up the silicon gun and apply small amount all over the edges of the midframe.

Putting too much can make a mess after pressing it together, so just spread it over the edge.

On the right side, where the battery would protrude a bit, I decided to put a bit more silicon to make sure that any gap is not just air, but at least filled with silicon.

I also applied a bit more on the edges.

Be steady and slow – don’t rush it. The first silicon, you put, will most certainly cool down, until you finish putting the last. So take your time and apply it carefully. After it is done, align the back cover and put it on the silicon, you just laid. Fire the heat gun and melt that silicon back.

Press the back firmly until it pushes the silicon from the inside. Hold with your fingers on as many contact points as you can, until it has cooled down and solidified. Now, while it is still warm and soft, take a sharp plastic tool and slide over the edge where the silicon has came out, to gather the excess.

Now, you have it! The phone is put back together.

Don’t forget to put the SIM back.

After this mod, my phone had a very tiny opening on the right side between the back and the midframe, but since I had put a bit more silicon, I think its okay.

We turn it back on and… it works!

I am now charging it to 100%, after which I will calibrate the battery (to reset the battery stats). For this I recommend the Battery Calibration [ROOT] app.

After I use if for a couple of days I will update this post with some battery life statistics.